News Release Number: STScI-2008-30

August 5, 2008: Globular star clusters, dense bunches of hundreds of thousands of stars, have some of the
oldest surviving stars in the universe. A new study of globular clusters outside our Milky
Way Galaxy has found evidence that these hardy pioneers are more likely to form in dense
areas, where star birth occurs at a rapid rate, instead of uniformly from galaxy to galaxy.
Astronomers used NASA's Hubble Space Telescope to identify over 11,000 globular
clusters in the Virgo cluster of galaxies. Most are older than 5 billion years. The sharp vision
of Hubble's Advanced Camera for Surveys resolved the star clusters in 100 galaxies of
various sizes, shapes, and brightnesses, even in faint, dwarf galaxies. The images in this
photo show four members of the Virgo cluster of galaxies. Comprised of over 2,000 galaxies,
the Virgo cluster is the nearest large galaxy cluster to Earth, located about 54 million light-years away.